Stabilized hydrocarbon fuel oils



Patented Oct. 20, 1953 STABILIZED HYDROCARBON FUEL OILS Herschel G. Smith, Wallingford, and Troy L. Cantrell, Lansdowne, Pa., and John G. Peters, Audubon, N. J assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application August 28, 1950, Serial No. 181,936

4 Claims. 1

This invention relates to stabilized hydrocarbon fuel oils, and more particularly to furnace oils, diesel fuels, and the like, stabilized against discoloration, the formation of sludge, and undesirable degradation pro-ducts appearing after storage of the fuel. The invention is primarily concerned with fuels commonly referred to as "middle oil distillates, as will more fully appear hereinafter.

The storage of fuel oils, furnace oils, and the like is in many instances complicated by the formation of undesirable products in the fuel oils as evidenced in several ways. After prolonged periods of storage many fuels tend to discolor, and ultimately insoluble material is formed in the fuel. This insoluble material precipitates out and leads to the formation of sludge. These products, and possibly others remaining in the fuel oils, cause the clogging of screens, conduits and other parts of burners, the formation of deposits on burners, commonly referred to as toadstools," and exhibit additional undesirable properties.

The degradation of fuel oils upon storage is apparently due to the action of air in contact with the fuel, coupled with the effect of light, particularly ultraviolet radiation. This degradation is generally believed to be the result of three types of reactions. Two of these, oxidation and polymerization of unsaturates, probably account for a great deal of the contaminants appearing after prolonged periods of storage. In addition, where cracked distillates resulting from catalytic cracking operations are blended with fuel oil, the discoloration of the fuel and formation of sludge appears to be aggravated. This is probably due to the rearrangement or activation of sulfur compounds contained in the cracked distillates. In this active state such compounds may catalyze the oxidation and polymerization of unsaturated compounds and/or the sulfur compounds may react with the ole-finic hydrocarbons to form soluble polymers which discolor the fuel. In all probability, all of these reactions take place upon storage, so that fuels which have been stored for many months may be characterized by discoloration, the formation of insoluble material, acidity andother deleterious properties.

The discoloration of fuels is particulary aggravated in the case of fuels which have been ex posed to light while under storage conditions. This difficulty is encountered with both cracked and uncracked fuels, although the problem appears to be serious in the case of uncracked fuels only when high sulfur stocks are involved 01 the sulfur is in a particularly active state.

An acceptable fuel for use in oil burners and diesel engines must, of course, be free from any tendency to clog filter screens and the numerous fine passages and openings present in fuel oil burners and in diesel engines. The fuel oil used in such equipment can interfere with the performance of various parts in several ways, among which are clogging, gumming, and corrosion. Particularly detrimental to good performance are sediments, which may be of the so called casual or non-casual" types. Casual sediments include sand, dirt, iron rust, dust, water, emulsions and miscellaneous debris. Casual sediments may be avoided by simply keeping the original oil clean and free from extraneous insoluble materials. The non-casual sediment is that sediment which may form in an oil during use or storage. sediment is an organic material originating mainly in oxidation and polymerization of all, or a portion of, the oil. As has been stated, this oxidation and polymerization results from the presence of oxygen or air and probably also is due to the presence of certain active sulfur compounds. The non-casual sediments may be very finely divided so as to form a sediment clogging small openings and fine pores of filters; in some cases they further coagulate in the form of coarser sediment forming massive deposits which clog filters and other parts of equipment.

The clogging of copper or copper bearing screens and filters in burners and other equipment is encountered to some extent with uncracked fuels, particularly if petroleum acids are not neutralized or washed out; therefore steps of neutralization and washing should be taken for any distillates containing materials of high neutralization number. In addition, trouble may also be encountered with furnace oils containing cracked distillates through the action of socalled oxyacids which are frequently developed in cracked fuels. There appears to be a tendency for such acids to form reaction products with the copper and copper bearing screens and filters.

These products tend to coat the wires so as to clog or reduce the size of the open mesh of openings such that even fine insoluble matter will clog them.

The tendency of fuels to clog filters varies with different fuels. However, certain fuels comprising a mixture of uncracked and cracked distillates have a greater tendency to form the non-casual sediment than do the cracked fuels alone. This is probably due to the fact that the decomposition products are less soluble in the uncracked distillates and therefore tend to precipitate out. As pointed out, although the de- Such velopment and settling out of insoluble matter is particularly prevalent with mixtures of cracked and uncracked distillates, this action appears to be more pronounced for high sulfur distillates, either cracked or-uncracked.

Acute trouble due to these problems is not likely to be developed with screens and filters in a system where fresh stocks that have not been in storage for a long time are employed.- I-Iowever, difiiculties are likely to be encountered by users of furnace oils who have allowed" furnaces to remain inactive and the "oil. to 1'8?" Insuch cases the development and settling outof main in storage over the summer months;

some insoluble matter may thus be concentrated in the first pumpings when the furnaceis'started this'increases the life ofthe filter andeliminates frequent shut-downs and operational'failures.

It.- is therefore an object of this invention to provide hydrocarbon fuel oils having improved stability onstorage,

More particularly, itis an object of. this invention to provide hydrocarbon fuel oils of im-'- proved stability against the formation of. un-

desirable colorbodies as. well as the development and settling out of insoluble matter on storage;

Another object. of this invention is to provide improved hydrocarbon fuels having substantially non-clogging tendencies to screens and, filters" and having a relatively. long induction period.

These and other objects are accomplished by the present invention wherein we. provide im proved fuels, stabilized against the formation of undesirable color bodies and against-sludge;

comprising. a major amount of av hydrocarbon fuel oil and a minor amount,- suflicient 'to inhibit the formation of insoluble matter and undesirable colorbodies, of a metallo compound obtained by reacting an aqueous slurry of a. metal hydroxide selected from the group'consistin'g of."

barium; strontium, magnesium. and calcium hydroxideswith formaldehyde at-a mildly elevated temperature and condensing the resulting product with. aniline and a. mono-alkyl phenol having.4 to--12 carbon atoms in the alkyl substituent...

The metallo compound'which isadded to fuel oils-in accordance with. ourinvention, described and claimed in the. copending application-of Smith, Cantrell. and Peters, Serial No. 790,440, filed. December 8, 1947, now-U. S. Patent. No;- 2',545,l13. As showntherein, the meta-11o compound is prepared by firstreacting an aqueous-slurry of the metal hydroxide and form.- aldehyde at a mild-1y elevated temperaturer say 160 F., but not exceeding200 F. The exactnature of this reaction product is unknown, but. the reaction product contains combined therein: the metal of the metal hydroxide. This product is-then condensed with aniline and amono-alkyl phenol having from 4 to! 12 carbon atoms'in the alkyl substitu'en-t. The condensation between the reaction product of themetal hydroxideand formaldehyde, and the aniline and phenol -prceeds spontaneously upon mixing the reactants; Since the reaction is exothermic, care should betaken not to allow the. temperature" to exceed.

about 200 F1, otherwise dark colored, high-1y resinous, insoluble products may result. After the condensation is completed, the temperature is raised to distill off all water, both that formed in the condensation and added with the reactants. There'actants'are preferably employed in the proportions of 1 mol of metal-hydroxide, 2 to 4 mols of formaldehyde, 0.5 to 1.0 mol of aniline and 2 to 4 mols of the mono-alkyl phenol.

The mono-alkyl phenols used in preparing the metallo compound have from 4 to 12 carbon atoms the alkyl substituent. Thus, the alkyl substitirent includes normal or branched chain butyl; amyl, hexyi, heptyl, octyl, decyl and dodecyl'radicalsi- A. preferred alkyl substituent is the tetramethylbutyl radical. The mono-alkyl phenols-"are preferably obtained by alkylating in knownmanner, in the presence of concentrated sulfuric acid, phenol with olefins having from 4 to 12carbon atoms. Olefins, such as butene-l, isobutylene, the amylenes, di-isobutylene and triisobutylene are conveniently employed. It is preferred. to conduct the alkylation with diis'obirf' tylene since the'resultin'g' product is primarily para tetramethylbutyl phenol.

In view of thejmultiple points of therespectiv'ei" molecules at which the reactants may react, it is believed that a mixture of compounds is obef tain'ed. The designation of the'reaction'prodirct as a metallo compound is intended to'cover' all thecoinpound's present therein.

The following example illustrates a"'prepar'a-" tion of a typical metallo compoun'cl'used" inou'r fuel oil compositions.

EXAMPLE. -1

Into a jacketediron. reaction vessel. (N0; 1)

were charged 12.9 parts by weightof phenol. and

16.5 parts by'weight'o'f diisobutylene. The vessei was closed and the mixture agitated. Then 0.6 part by weight of 94-98 per cent sulfuric acid was added. Cold Water was run, through the jacket 'of' methylbutyl phenol was dissolved in 73 parts by" weight'ofamineral lubricating oil. v

Into an enamel lined reaction. vessel (No'."2)'- were chargedjlfi by weight of calcium'hyd'roxid with sufficient water 'to'makea slurry to which was'added 14.9 parts by weight of a 3 7 per cent by weight aqueous solution of formaldehyde.

The reactants were heated. to a, temperatureofj ""?v for "twohours. Thereafter, the reaction product 'Qf'the'caIcium hydroxide and formaldehyd was added to the minera1 oil solution of The reactants in the above example were in the molar proportions of about 1.0-mol of calcium hydroxide, 311- molsof rormaldehyde 2r3- mols of para tetramethylbutyl phenol and 0.7 mol of aniline.

We have found that the above-described metalcompounds may be compounded with a wide variety of hydrocarbon fuel oils to impart advantageous properties thereto. For example, both cracked and uncracked distillates and mixtures thereof in the fuel oil boiling range, that is, hydrocarbons boiling within the range of about 350 to 750 F'., are stabilized against oxidative deterioration and the formation of undesirable contaminants by a minor amount of the metallo compounds set forth. By way of illustration, some of the most commonly used fuel oils which are benefited by the metallo compounds are numbers 1, 2 and 4 fuel oils, the requirements for which are specified in A. S. T. M. specification D396-48T. These specifications appear hereinafter under Table I.

Table I equipment. The amount of metallo compound used is sufficient to stabilize the fuel oil against the formation of sludge or insoluble bodies, and in general, small amounts, from 0.001 to 5.00 per cent by weight on the fuel oils, will sufiice. The metallo compound may be dispersed in fuel oil stocks directly by simple mixing, or it may be introduced to the fuel oil in the form of a concentrate of the metallo compound in a minor amount of a fuel oil or hydrocarbon solvent which may be more readily blended with fuel oil.

To determine the effectiveness of the said metallo compounds on inhibiting the formation of sludge and stabilizing the color of the oil, tests were conducted on a No. 2 furnace oil both before and after treatment with the metallo compound of Example I. Of these tests, an oxidation test was selected as most indicative of the environment which appears to induce the formation of Grade of Fuel Oil No. 1A distillate oil intended for vaporizing pottype burners and other burners requiring this grade of fuel No. 2-A distillate oil for general purpose domestic heating for use in burners not rel; l 1 1lll'lX1g No. 1 Fuel 1 No. 4An oil for burner installation not e q u i p p e d with preheating facilities Flash Point, F Pour Point, F Water and Sediment, percent by Carbon Residue on 10% Bottoms, percent.-. Ash, percent by Wt Distillation, F.:

10% at F 90% at F End Point, F

Viscosity, SUV, seconds, 100 F Viscosity, Kinematic, Centistokes, 100 F.

Gravity, API

Copper Strip Test, 122 F., 3 Hr Corrosion Test, 122 F., 3 Hr min. max. 0

max.

max.

min. 100 or legal...

min. 130 or legal. max. 20. max. 0.50.

max

max. 0.

max.

max.

max. min.

max. min.

As further illustrative of fuels which are benefited by the metallo compounds, the specifications for certain diesel fuel oils as prescribed by A. S. T. M. Designation: D9'I5-48T are set forth in Table II.

Table II sludge and undesirable color bodies. For this purpose A. S. T. M. oxidation test D943-47T was modified somewhat by eliminating the iron and copper catalyst coils as prescribed by the test. In other words, the A. S. T. M. test procedure as Grade of Fuel Oil No. 1DA volatile distillate fuel oil for engines in service requiring frequent speed and load changes No. 2-13-11 distillate fuel oil of low No. 4DA fuel volatility for enoil for low and ginesinindustrlal medium speed and heavy mobile engines service Flash Point, F min. or legal..

Pour Point, F max 0 Water and Sediment, percent by Vol max. trace- Carbon Residue on 10% Bottoms, Percent max. 0.15..

Ash, Percent by Wt Distillation:

max.

Viscosity, SUV, seconds, 100 F Sulfur, Percent by Wt Copper Strip Corrosion Octane Number min. 100 or legal min. or legal. mm. 20 max. 20.

max. 0.50.

max. 0.10.

mnx. 125. min. 45. max. 2.0.

min. 25.

In accordance with our invention, small proportions of the herein-described metallo compounds in fuel oils will substantially reduce the tendency to form insoluble constituents, undesirable color bodies and the tendency of the fuel to clog screens and filters in burners and other outlined in test D943-47T was followed employing the glass parts of the A. S. T. M. oxidation assembly for blowing a sample of the fuel oil with oxygen. Briefly, the test employed comprised placing a 300 cc. sample of the fuel oil in a flask 2'5 immersed in an oil bath at 3000 F. and blowingoxygen -throu'gh =the sample for a period of two hours at the rate "of litersof oxygerr per hour;- The sample was-then filtered-and the-weight-of insoluble material or sludgeformed was noted. The color-was*also*noted. This test bears the designation Gulf Method- 327, Modified."

1 fi ablellfhereinbelow shows the results of the above described" oxidation test-when conducted on a No. 2furnace-oil comprised of '75-per cent uncracked 25 per cent cracked distillates both before andafter-improvementby the addition of 0.02-per cent byweightof'the reaction product-prepared according to Example I.

Table 'III Unlui- I Iin'proved' proved-Oily, Oil" Gravity, API Color, Neutralization No Carbon Residue, Percent Oxidation Test, Method 327, Gul

Color, NPA, Filtered Sludge. Percent Another test was devised to simulate, on an accelerated basis, the conditions and eifectsprevailing upon long exposure of fuel oil to copper screens in burner systems; In brief; tl'ietest'com prises exposing a sample of fuel oil in the presence of a copper screen to ultraviolet light and observing the efiects after the lapse of a specific period of time. quartz tubes holding 100 cc. samples, the-quartz tubes providing full effect for the ultraviolet light without the error that may occur'withglass tubes which absorb actinic light rays. A 2 by 3 in., 60 mesh, copper screen, bent in the form of'a-cylinder, was suspended in the middle of; the oilin" each quartz tube by means of two fine Wire hangers placed through two side slotsof the top cork: The, tubes were then placed in a weatherometer ata di's'tance'ofabout 'inches' from a sourc'e of ultraviolet light derived from a standard type C 3B" Evereauy" carbon arc solariunfi unit. The temperature was-maintained'at'lll" F., andthe ex osure cohtlriiledfbi' a period'of 24 hours, after which the color and general appearance of the oil were noted. This test bears the designation "Gulf Method 332, Modified.

EXAMPLE III Table IV hereinafter shows the results of the 55 No. 2 oil employed for-Example 11 both before ultraviolet light test wh'ri cofidiicte'd onthe same and after improvement by th'e'a'ddition' of 0.01 per cent by weight of the product prepared according to Example I.

Table IV Unimproved Improved Oil Oil Ultraviolet Light Stability, Method 332, Gull Mod. Quartz tube, 111 F., 24 Hr., 6 Sq. in Copper Screen: I

Color, NPA 7.5 4.7 5. Appearance V precipitate bright.

'It"isap'parent from the above'data that the niet'allo" compounds described hereinabove re-' markably inhibit'the formation of sludge in furnace oils, and further, substantially stabilize the color thereof. Thus very small amountsof the The oil was placed in standard 8 inhibitors set forth are sufiicient for" retarding the development of c0101 and sediment in fuel oils upon aging.- 1 In addition-,'.themetal in the metallo compound gives a detergent action to the additive which facilitates maintaining filters-and burners-free from deposits and sludge;

Undercertain conditions, however; the rusting of iron surfaces ofstorage tanks or other-equip mentmay be encountered, particularly where promoted by the presence of water. For most purposes the improved fuel oils of our invention are stabilized againstthe formation of rust; but where extreme conditions are'enoountered' which unduly aggravate' rust and'corrosion, it=is*con'- temple-ted within the-scopeof our invention-toincludein the fuel-oils other inhibitors-to retard theformation of rust and" prevent corrosion; Such rust and corrosion inhibitors are-well knowrf in the art and a wide variety of them can-be employed where necessary.

Resbrtmay be had to such modifications and variations as fall within the spirit of the invention and the scope of the appended claims.

What we claim is:

1'; A" fuel'oil" composition comprising a major amount Ufa-hydrocarbon fuel oil and a minor amount; sufiicien't to stabilize the fuel oil against the formation of sludge, of the reaction product prepared by'reacting an aqueous slurry of 1 mol of a metal hydroxide selected from the group consisting of barium, strontium, magnesium and calcium'hydro'x'ides wi'th" from 2 to '4 mols 'of formaldehyde at a temperature not exceeding 200'fF-5 an'dc'onden'sing the resulting productwith from 0.5 to 1 mol of aniline and from 2 to 4-mo1s of a mono-alkyl phenol havingfrom 4to 12 carbon atoms in the alkyl substituent. V I v 2. The composition of cla'irn'l wherein the said reaction productis present in an amountof from" 0001 to 5.00 per cent by weight on the fuel=oil;

3. A fuel oil composition comprising a major amount of a hydrocarbon fuel oil and a minor amount, sufficient to stabilize the fuel oil against ma formation of sludge, of the reaction product prepared by reacting 'an aqueous slurry" of "1 m'ol or a me'tal liydroxide selected from the group consisting of barium, strontium; magnesiumand calcium hydroxides with from 2 to 4-mols-,of formaldehyde at a temperature not exceeding 200 Ffandcondensing the resulting product at a temperature not exceeding 200 F. with from 0.5 to 1 mol of aniline and from 2 to 4 mols of a mono-alkyl phenol having from 4 to 12 carbon atoms in the alkyl substituent.

4. Afuel oil composition comprising a major amount of 'a" hydrocarbon fuel oil and a minor amount, sufficient to stabilize the fuel oil against the formation of sludge, of the reaction product prepared by reacting an'aqueous slurry of 131101151? calcium hydroxide with 3 mols 'of'formaldehy'de at a temperature of about 160 F., andcondensing the resulting'p'roduct with about 0.7 mol of aniline and 2.3 mols of para tetramethylbutyl pheno'latatemperature not exceeding 200 I-IERSCHEI -G SMITH; TROY L. cANrRnLn JOHN G. PETERS.

References Cited in the file" of this patent- UNITED STATES PATENTS Number Name I Date 2,431,011 Zimmer et al. Nov. 18,- 1947 2545,113 Smith et a1; -l Mar. 13,--l1= 

1. A FUEL OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF A HYDROCARBON FUEL OIL AND A MINOR AMOUNT, SUFFICIENT TO STABILIZE THE FUEL OIL AGAINST THE FORMATION OF SLUDGE, OF THE REACTION PRODUCT PREPARED BY REACTING AN AQUEOUS SLURRY OF 1 MOL OF A METAL HYDROXIDE SELECTED FROM THE GROUP CONSISTING OF BARIUM, STRONTIUM, MAGNESIUM AND CALCIUM HYDROXIDES WITH FROM 2 TO 4 MOLS OF FORMALDEHYDE AT A TEMPERATURE NOT EXCEEDING 200* F. AND CONDENSING THE RESULTING PRODUCT WITH FROM 0.5 TO 1 MOL OF ANILINE AND FROM 2 TO 4 MOLS OF A MONO-ALKYL PHENOL HAVING FROM 4 TO 12 CARBON ATOMS IN THE ALKYL SUBSTITUENT. 